In the last issue I talked about the symmetrical Whole tone scale. For this issue I thought I’d follow on from that and talk about another symmetrical scale – the Half-whole diminished scale. As with the Whole tone, the Half-whole diminished scale has an unconventional and ‘outside’ sound to it. Although it’s most commonly heard in jazz, it has a dissonant character to it that can sound cool for metal solos and riffs.

EXERCISE 1

The scale is comprised entirely of an alternating series of half (H) and whole (W) steps. This can be seen in Exercise 1, shown here in the key of E on one string. Due to this repeating series of semitone and tone intervals, you get an eight note scale.

A great thing about the Half-whole diminished scale is that the fingering across the strings is really easy to remember. Here in the key of A, on the first string you use a 4-2-1 finger pattern and on the second string you reverse this for a 4-3-1 fingering. This is then repeated on strings three and four. You move up a fret for strings five and six but the finger groupings remain the same. It ends with a first finger position shift to the root note. To play it all over the neck, simply move the pattern up or down three frets at a time.

The scale is most often heard in a jazz context over an altered dominant seventh chord resolving to the tonic. This is because it contains the notes of a dominant seventh chord (1-3-5-b7) along with three of the four possible altered notes (plus a major 6th). The available chromatic notes to add to a dominant seventh chord are: b9, #9, b5, #5. The Half-whole diminished scale has the b9, #9 and b5. As such, its formula can be spelled as: 1-b9-#9-3-b5-5-6-b7. If this is a bit confusing, keep in mind that b9 is the same as b2, and #9 is the same as b3. Its use in jazz is illustrated in Exercise 3. Played with swung eighth notes in the key of D minor, A Half-whole diminished is used over the A7(b9) chord before resolving to the Dm7.

Putting all the theory aside, the scale just has a pretty sick and demented sound to it! This makes it great for writing cool riffs – be it single note or with power chords (as in Exercise 4). This is a simple, chugging riff that uses power chords based off of the first five notes of the Half-whole diminished scale.

This is a short lead phrase to be played with the riff from Exercise 4. The first two bars feature some standard minor scale licks to establish the overall E minor tonality. It then moves into an alternate-picked descending sequence using an E Half-whole diminished scale before resolving to the tonic. Although here it’s played over a riff based off the same scale, you can use the Half-whole diminished over any minor-key riff or chord progression. This is because while it does contain the notes of a dominant 7 chord (major), it also contains the notes of a minor 7 chord (1-b3-5-b7)and can be viewed as a natural minor scale but with the dissonant b2 and b5 intervals (plus a maj6 and maj3). As long as you don’t accentuate the ‘outside’ notes and resolve to a chord tone, it will work.

Alex Skolnick of Testament often employs the Half-whole diminished scale (as well as its cousin, the Whole-half diminished scale) in his solos. So check out some Testament for more examples, and give it a go yourself.